The Royal Family loves to keep things flawlessly refined and official, whether in public outings or on social media.

So when that perfect facade slips every now and then, we, the commoners, just can't get enough.

On Thursday, it seemed the palace had committed a rather delicious gaffe on Instagram - and naturally, it was quickly picked up by eagle-eyed reporters.

That face when a fan-run royals page calls you by the wrong name. (Getty)

In a screenshot captured by news.com.au, it appeared Buckingham Palace had mistakenly called Princess Eugenie the wrong name on Instagram in a post about her October 12 wedding.

“This exclusive mug issued in commemoration of the wedding of HRH Princess Beatrice of York and Mr Jack Brooksbank is now available for purchase by following the link in the description,” the caption of the since-deleted post read.

Here's the amended version:

As far as royal slip-ups go, calling a newlywed princess by her older sister's name is as awkward as it gets. Unfortunately, however, this particular boo-boo really is too good to be true.

The Instagram account that allegedly misnamed Eugenie, @buckinghamroyal, is not part of the Royal Family's official accounts; it seems to be a fan-operated one.